[test-runner] Setting concurrency > 1 using chrome launcher can hang and timeout on Ubuntu

[DavidPeicho]

Information

• Chrome: v115.0.5790.102
• OS: Ubuntu 20.04
• Test Framework: Mocha
• @web/test-runer@0.17.0

Issue

Setting the concurrency to anything other than 1 (or basically not setting it since it fall back to hardware count div 2) can make tests hang and timeout on Chrome on Ubuntu. I couldn't reproduce this issue neither on Mac M1, Mac x86, and Windows 10.

Failing tests are always asynchronous:

it('my-test', async function () {
    await scene.load(...);
    ....
});

[DavidPeicho]

Funny thing: Setting it to 1/2 on a Mac M1 Ventura hangs as well